CVE-2024-46730: Integer Underflow (Wrap or Wraparound)

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Ensure array index tginst won't be -1 WHY & HOW tginst will be a negative if timinggeneratorcount equals 0, which should be checked before used. This fixes 2 OVERRUN issues reported by Coverity...